This presentation discusses water chemistry and drinking water quality in India. It provides background on water sources in rural India and key water quality issues. These issues include overextraction of groundwater leading to shortages, and contamination putting millions of people at health risks. The presentation then examines the critical water quality parameters to test like alkalinity, hardness, arsenic, chloride, coliform, pH, fluoride, iron and turbidity. It describes the testing methods and instruments used and health impacts of parameter levels outside acceptable limits. The goal is to assess water quality and safety for drinking.

1. PRESENTATION ON
WATER CHEMISTRY
Environmental Engineering
Madhur Devkota
Bikalp Acharya

2. D R I N K I N G W AT E R Q U A L I T Y

3. Background
1. Rural India has more than 700 million people residing in
about 1.42 million habitations spread over 15 diverse
ecological regions.
2. 85 % of rural population in India is solely depended on ground
water, which is depleting at a fast rate.
3. India has 16% of the world’s population and 4% of its fresh
water resources.
4. Ninety 2% groundwater extracted is used in the agricultural
sector, five and 3 % respectively for industrial and domestic
sector.

4. Water Quality Problems
1. Excessive extraction of ground water make water critical critical
during summer months in many parts of the country.
2. 70 million people in 20 states are at risk due to excess fluoride and
around 10 million people are at risk due to excess arsenic in
ground water.
3. Ingress of seawater into coastal aquifers as a result of over-
extraction of ground water has made water supplies more saline,
unsuitable for drinking and irrigation.
4. It is estimated that around 37.7 million Indians are affected by
waterborne diseases annually, 1.5 million children are estimated
to die of diarrhoea alone and 73 million working days are lost due
to waterborne disease each year.

5. Water Pollution
Polluting
Agents*
(Public Health
Services)

6. Contribution of each Polluting Agents

7. Water Quality Surveillance
Critical Parameters to be tested for assessing water quality
Alkalinity* –
Sources – i) salts of weak acids (CO3-2, HCO3-, OH-….)
ii) *Algae consuming CO2 *
Impact – i) Induces bitter taste, unpalatable
ii)Foul pipes and water system appurtenances
Acceptable Limit Limit for Rejection Result
200 mg/L 600 mg/L 512 mg/L

8. Hardness –
defined as concentration of multi-valent metallic cation in soln
Sources – i) dissolved Ca++ & Mg++ and their salts
ii) Other ions Fe++, Mn++, Al+3 (in small quantities)
iii) Area where top-soil is thick & lime stone formation are
present
Impact – i) Consumes soap*
ii) Scale formation in boilers and pipes*
Acceptable Limit Limit for Rejection Result
75 mg/L 110 mg/L 20 mg/L

9.  Arsenic –
Sources – i) Natural source:
volcanic ash, weathering of arsenic containing minerals and ores
ii) Artificial source:
Smelter emission*, Mining waste
Wood preservatives such as Chromated copper arsenate
Arsenic bearing fertilizers, Deposition from coal combustion
Impact – i) Hinders aquatic life
ii) Increases risk of cancer* and other various acute diseases*
Cases- High Arsenic contamination in Ground water in West Bengal*
and Bangladesh*
Acceptable Limit Limit for Rejection
0.05 mg/L 0.05 mg/L

10. Instrument used
Absorption vs. Concentration
Spectrophotometer
graph

11.  Chloride –
Sources – i) Nonpoint source:
a) Natural*
b) Agriculture*
c) Residential and Urban*
ii) Point source *
Reagent Used for test- Indicator: K2CrO4; Titrant: N/70 AgNO3 soln
Impact – i) >250 mg/L the taste is salty
ii) Evapotransportation increase salinity  makes crops difficult
to absorb water *
Application- Used as a tracer*
Acceptable Limit Limit for Rejection Result
200 mg/L 600 mg/L 36 mg/L

12.  Total Coliform –
Sources – i) Contamination of animal feces in soil & ground
water
ii) Agricultural runoff
iii) Effluent from septic systems or sewage
discharges
Reagent Used for test- Beef Extract, Lactose & Peptone
Impact – Most coliform bacteria do not cause illness however…*
i) Positive fecal coliform results fecal pollution
ii) Stomach and intestinal illness*
iii) Waterborne pathogenic*
Acceptable Limit Limit for Rejection Result
0 1 coliform colony 460 per 100 ml (in waster water)
per 100 ml 0 per 100 ml (in tap water)

13. Instrument Used
Autoclave- for sterilizing Incubator- for incubation
broth for 3hrs of organism at 35oC

14.  pH–
Cause of pH change–
i) Depletion of CO2 in water increases pH
ii) High pH in lake during summer *
iii) Increases due to increase of carbon-based mineral
molecules suspended in the solution
iv) Is decreased by Acid rain
Impact – i) corrosive effects of acidity
ii) high or low pH harm fish by denaturing cellular
membranes.
iii) as the pH approaches 5, non-desirable species of
plankton and mosses may begin to invade at bottom
iv) aesthetic problems dur to low pH* & high pH

15. Acceptable Limit Limit for Rejection Result
7-8.5 6.5-9.2 7.63
Instrument Used–
pH meter

16.  Fluoride –
Reagent Used for test- SPANDS solution, Zirconyl-acid reagent, reference
solution, sodium ardenate solution
Health Impact – i) Immediate symptoms include digestive disorders, skin
diseases, dental fluorosis.
ii) Fluoride in larger quantities (20-80 mg/day) taken over a period
of 10-20 years results in crippling and skeletal fluorosis which is
severe bone damage.
Affected states – Andhra Pradesh, Assam, Bihar, Chattisgarh, Gujarat, Haryana,
Jharkhand, Karnataka, Kerala, Madhya Pradesh, Maharashtra,
Orissa, Punjab, Rajasthan, Tamil Nadu, Tripura, Uttar Pradesh,
West Bengal
Instrument Used– Spectrophotometer

17.  Iron –
Reagent Used for test- Conc HCl, Hydroxylamine solution, Ammoniun acaetate, sod.
acetate soln, phenanthroline soln, stock iron soln
Health Impact – i) A dose of 1500 mg/l has a poisoning effect on a child as it can
damage blood tissues.
ii) Digestive disorders, skin diseases and dental problems.
Affected states – Arunachal Pradesh, Assam,Bihar, Chattisgarh, Jharkhand, Jammu and
Kashmir, Karnataka, Kerala, Manipur, Meghalaya, Mizoram, Madhya
Pradesh, Maharashtra, Nagaland, Orissa, Punjab, Rajasthan, Sikkim,
Tripura, Tamil Nadu, Uttar Pradesh, West Bengal, A&N Islands,
Pondicherry
Acceptable Limit for Result
Limit Rejection
0.3 mg/L 1 mg/L 0.3 mg/L

18. Turbidity –
Sources – presence of iron, chlorine, suspended particles.
Instrument used for test- Nephelometer
Impact-
1. Aesthetic value
2. High turbidity may be an indication of Iron and other impurities
Instrument Used– Nephlometer

19. THANKYOU !!